Automatic doors are doors that are powered open or powered closed or both. If an automatic door is powered open only, then it is conventionally spring closed or hydraulically closed. Automatic doors typically employ a sensor or switch to activate the door. The sensor detects approaching traffic and may be a motion sensor, infrared sensor, or pressure sensor. The switch is conventionally operated manually and may take the form of a push button, swipe card, or other available switch type access or security system. Alternatively the switch may be activated by pushing or pulling the door, so that once the door detects the movement it completes the open and close cycle. These are also known as power-assisted doors.
Swinging doors are hinged and pivot around an axis in an inward or outward direction or both. Automatic swinging doors are coupled to a source of torque, that is, a door operating apparatus, for providing the force necessary to pivot the door open or closed, or both. Most commercially available door operating apparatuses are electromechanical or electrohydraulic and are positioned above the door in an overhead position for ease and economy of installation. Most commercially available door operating apparatuses are spring closed.
It is sometimes desirable to position the door operating apparatus in a sub-floor stratum. The Tormax Model TN (“Tormax” is registered trademark of Landert Motoren AG, Büach-Zürich, Switzerland) is a floor mounted door operator and is manufactured as an automatic door operator. The Model TN is an underground hydraulic closer with a remotely mounted electric pump system that pushes hydraulic fluid within a floor closer to operate a door. The pump system and electronics are mounted remotely and are not mounted underground. The Model TN is a hydraulic device and is not considered an electromechanical door operating apparatus. Commercially available electromechanical door operating apparatuses designed for use underground or in a sub-floor stratum are unknown.
U.S. Pat. No. 6,176,044 discloses a kit and method for retrofitting electromechanical or equivalent door operating apparatuses. The retrofit kit shown in this patent is employable for converting any door operating apparatus for operating a swinging door from overhead use to underground use. The retrofit kit has had general success in the market place.